rpc_pipefs: allow rpc_purge_list to take a NULL waitq pointer
[linux-3.10.git] / net / sunrpc / rpc_pipe.c
1 /*
2  * net/sunrpc/rpc_pipe.c
3  *
4  * Userland/kernel interface for rpcauth_gss.
5  * Code shamelessly plagiarized from fs/nfsd/nfsctl.c
6  * and fs/sysfs/inode.c
7  *
8  * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no>
9  *
10  */
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/string.h>
14 #include <linux/pagemap.h>
15 #include <linux/mount.h>
16 #include <linux/namei.h>
17 #include <linux/fsnotify.h>
18 #include <linux/kernel.h>
19 #include <linux/rcupdate.h>
20
21 #include <asm/ioctls.h>
22 #include <linux/poll.h>
23 #include <linux/wait.h>
24 #include <linux/seq_file.h>
25
26 #include <linux/sunrpc/clnt.h>
27 #include <linux/workqueue.h>
28 #include <linux/sunrpc/rpc_pipe_fs.h>
29 #include <linux/sunrpc/cache.h>
30 #include <linux/nsproxy.h>
31 #include <linux/notifier.h>
32
33 #include "netns.h"
34 #include "sunrpc.h"
35
36 #define RPCDBG_FACILITY RPCDBG_DEBUG
37
38 #define NET_NAME(net)   ((net == &init_net) ? " (init_net)" : "")
39
40 static struct file_system_type rpc_pipe_fs_type;
41
42
43 static struct kmem_cache *rpc_inode_cachep __read_mostly;
44
45 #define RPC_UPCALL_TIMEOUT (30*HZ)
46
47 static BLOCKING_NOTIFIER_HEAD(rpc_pipefs_notifier_list);
48
49 int rpc_pipefs_notifier_register(struct notifier_block *nb)
50 {
51         return blocking_notifier_chain_cond_register(&rpc_pipefs_notifier_list, nb);
52 }
53 EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_register);
54
55 void rpc_pipefs_notifier_unregister(struct notifier_block *nb)
56 {
57         blocking_notifier_chain_unregister(&rpc_pipefs_notifier_list, nb);
58 }
59 EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_unregister);
60
61 static void rpc_purge_list(wait_queue_head_t *waitq, struct list_head *head,
62                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
63 {
64         struct rpc_pipe_msg *msg;
65
66         if (list_empty(head))
67                 return;
68         do {
69                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
70                 list_del_init(&msg->list);
71                 msg->errno = err;
72                 destroy_msg(msg);
73         } while (!list_empty(head));
74
75         if (waitq)
76                 wake_up(waitq);
77 }
78
79 static void
80 rpc_timeout_upcall_queue(struct work_struct *work)
81 {
82         LIST_HEAD(free_list);
83         struct rpc_pipe *pipe =
84                 container_of(work, struct rpc_pipe, queue_timeout.work);
85         void (*destroy_msg)(struct rpc_pipe_msg *);
86         struct dentry *dentry;
87
88         spin_lock(&pipe->lock);
89         destroy_msg = pipe->ops->destroy_msg;
90         if (pipe->nreaders == 0) {
91                 list_splice_init(&pipe->pipe, &free_list);
92                 pipe->pipelen = 0;
93         }
94         dentry = dget(pipe->dentry);
95         spin_unlock(&pipe->lock);
96         rpc_purge_list(dentry ? &RPC_I(dentry->d_inode)->waitq : NULL,
97                         &free_list, destroy_msg, -ETIMEDOUT);
98         dput(dentry);
99 }
100
101 ssize_t rpc_pipe_generic_upcall(struct file *filp, struct rpc_pipe_msg *msg,
102                                 char __user *dst, size_t buflen)
103 {
104         char *data = (char *)msg->data + msg->copied;
105         size_t mlen = min(msg->len - msg->copied, buflen);
106         unsigned long left;
107
108         left = copy_to_user(dst, data, mlen);
109         if (left == mlen) {
110                 msg->errno = -EFAULT;
111                 return -EFAULT;
112         }
113
114         mlen -= left;
115         msg->copied += mlen;
116         msg->errno = 0;
117         return mlen;
118 }
119 EXPORT_SYMBOL_GPL(rpc_pipe_generic_upcall);
120
121 /**
122  * rpc_queue_upcall - queue an upcall message to userspace
123  * @pipe: upcall pipe on which to queue given message
124  * @msg: message to queue
125  *
126  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
127  * A userspace process may then later read the upcall by performing a
128  * read on an open file for this inode.  It is up to the caller to
129  * initialize the fields of @msg (other than @msg->list) appropriately.
130  */
131 int
132 rpc_queue_upcall(struct rpc_pipe *pipe, struct rpc_pipe_msg *msg)
133 {
134         int res = -EPIPE;
135         struct dentry *dentry;
136
137         spin_lock(&pipe->lock);
138         if (pipe->nreaders) {
139                 list_add_tail(&msg->list, &pipe->pipe);
140                 pipe->pipelen += msg->len;
141                 res = 0;
142         } else if (pipe->flags & RPC_PIPE_WAIT_FOR_OPEN) {
143                 if (list_empty(&pipe->pipe))
144                         queue_delayed_work(rpciod_workqueue,
145                                         &pipe->queue_timeout,
146                                         RPC_UPCALL_TIMEOUT);
147                 list_add_tail(&msg->list, &pipe->pipe);
148                 pipe->pipelen += msg->len;
149                 res = 0;
150         }
151         dentry = dget(pipe->dentry);
152         spin_unlock(&pipe->lock);
153         if (dentry) {
154                 wake_up(&RPC_I(dentry->d_inode)->waitq);
155                 dput(dentry);
156         }
157         return res;
158 }
159 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
160
161 static inline void
162 rpc_inode_setowner(struct inode *inode, void *private)
163 {
164         RPC_I(inode)->private = private;
165 }
166
167 static void
168 rpc_close_pipes(struct inode *inode)
169 {
170         struct rpc_pipe *pipe = RPC_I(inode)->pipe;
171         int need_release;
172         LIST_HEAD(free_list);
173
174         mutex_lock(&inode->i_mutex);
175         spin_lock(&pipe->lock);
176         need_release = pipe->nreaders != 0 || pipe->nwriters != 0;
177         pipe->nreaders = 0;
178         list_splice_init(&pipe->in_upcall, &free_list);
179         list_splice_init(&pipe->pipe, &free_list);
180         pipe->pipelen = 0;
181         pipe->dentry = NULL;
182         spin_unlock(&pipe->lock);
183         rpc_purge_list(&RPC_I(inode)->waitq, &free_list, pipe->ops->destroy_msg, -EPIPE);
184         pipe->nwriters = 0;
185         if (need_release && pipe->ops->release_pipe)
186                 pipe->ops->release_pipe(inode);
187         cancel_delayed_work_sync(&pipe->queue_timeout);
188         rpc_inode_setowner(inode, NULL);
189         RPC_I(inode)->pipe = NULL;
190         mutex_unlock(&inode->i_mutex);
191 }
192
193 static struct inode *
194 rpc_alloc_inode(struct super_block *sb)
195 {
196         struct rpc_inode *rpci;
197         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
198         if (!rpci)
199                 return NULL;
200         return &rpci->vfs_inode;
201 }
202
203 static void
204 rpc_i_callback(struct rcu_head *head)
205 {
206         struct inode *inode = container_of(head, struct inode, i_rcu);
207         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
208 }
209
210 static void
211 rpc_destroy_inode(struct inode *inode)
212 {
213         call_rcu(&inode->i_rcu, rpc_i_callback);
214 }
215
216 static int
217 rpc_pipe_open(struct inode *inode, struct file *filp)
218 {
219         struct rpc_pipe *pipe;
220         int first_open;
221         int res = -ENXIO;
222
223         mutex_lock(&inode->i_mutex);
224         pipe = RPC_I(inode)->pipe;
225         if (pipe == NULL)
226                 goto out;
227         first_open = pipe->nreaders == 0 && pipe->nwriters == 0;
228         if (first_open && pipe->ops->open_pipe) {
229                 res = pipe->ops->open_pipe(inode);
230                 if (res)
231                         goto out;
232         }
233         if (filp->f_mode & FMODE_READ)
234                 pipe->nreaders++;
235         if (filp->f_mode & FMODE_WRITE)
236                 pipe->nwriters++;
237         res = 0;
238 out:
239         mutex_unlock(&inode->i_mutex);
240         return res;
241 }
242
243 static int
244 rpc_pipe_release(struct inode *inode, struct file *filp)
245 {
246         struct rpc_pipe *pipe;
247         struct rpc_pipe_msg *msg;
248         int last_close;
249
250         mutex_lock(&inode->i_mutex);
251         pipe = RPC_I(inode)->pipe;
252         if (pipe == NULL)
253                 goto out;
254         msg = filp->private_data;
255         if (msg != NULL) {
256                 spin_lock(&pipe->lock);
257                 msg->errno = -EAGAIN;
258                 list_del_init(&msg->list);
259                 spin_unlock(&pipe->lock);
260                 pipe->ops->destroy_msg(msg);
261         }
262         if (filp->f_mode & FMODE_WRITE)
263                 pipe->nwriters --;
264         if (filp->f_mode & FMODE_READ) {
265                 pipe->nreaders --;
266                 if (pipe->nreaders == 0) {
267                         LIST_HEAD(free_list);
268                         spin_lock(&pipe->lock);
269                         list_splice_init(&pipe->pipe, &free_list);
270                         pipe->pipelen = 0;
271                         spin_unlock(&pipe->lock);
272                         rpc_purge_list(&RPC_I(inode)->waitq, &free_list,
273                                         pipe->ops->destroy_msg, -EAGAIN);
274                 }
275         }
276         last_close = pipe->nwriters == 0 && pipe->nreaders == 0;
277         if (last_close && pipe->ops->release_pipe)
278                 pipe->ops->release_pipe(inode);
279 out:
280         mutex_unlock(&inode->i_mutex);
281         return 0;
282 }
283
284 static ssize_t
285 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
286 {
287         struct inode *inode = filp->f_path.dentry->d_inode;
288         struct rpc_pipe *pipe;
289         struct rpc_pipe_msg *msg;
290         int res = 0;
291
292         mutex_lock(&inode->i_mutex);
293         pipe = RPC_I(inode)->pipe;
294         if (pipe == NULL) {
295                 res = -EPIPE;
296                 goto out_unlock;
297         }
298         msg = filp->private_data;
299         if (msg == NULL) {
300                 spin_lock(&pipe->lock);
301                 if (!list_empty(&pipe->pipe)) {
302                         msg = list_entry(pipe->pipe.next,
303                                         struct rpc_pipe_msg,
304                                         list);
305                         list_move(&msg->list, &pipe->in_upcall);
306                         pipe->pipelen -= msg->len;
307                         filp->private_data = msg;
308                         msg->copied = 0;
309                 }
310                 spin_unlock(&pipe->lock);
311                 if (msg == NULL)
312                         goto out_unlock;
313         }
314         /* NOTE: it is up to the callback to update msg->copied */
315         res = pipe->ops->upcall(filp, msg, buf, len);
316         if (res < 0 || msg->len == msg->copied) {
317                 filp->private_data = NULL;
318                 spin_lock(&pipe->lock);
319                 list_del_init(&msg->list);
320                 spin_unlock(&pipe->lock);
321                 pipe->ops->destroy_msg(msg);
322         }
323 out_unlock:
324         mutex_unlock(&inode->i_mutex);
325         return res;
326 }
327
328 static ssize_t
329 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
330 {
331         struct inode *inode = filp->f_path.dentry->d_inode;
332         int res;
333
334         mutex_lock(&inode->i_mutex);
335         res = -EPIPE;
336         if (RPC_I(inode)->pipe != NULL)
337                 res = RPC_I(inode)->pipe->ops->downcall(filp, buf, len);
338         mutex_unlock(&inode->i_mutex);
339         return res;
340 }
341
342 static unsigned int
343 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
344 {
345         struct inode *inode = filp->f_path.dentry->d_inode;
346         struct rpc_inode *rpci = RPC_I(inode);
347         unsigned int mask = POLLOUT | POLLWRNORM;
348
349         poll_wait(filp, &rpci->waitq, wait);
350
351         mutex_lock(&inode->i_mutex);
352         if (rpci->pipe == NULL)
353                 mask |= POLLERR | POLLHUP;
354         else if (filp->private_data || !list_empty(&rpci->pipe->pipe))
355                 mask |= POLLIN | POLLRDNORM;
356         mutex_unlock(&inode->i_mutex);
357         return mask;
358 }
359
360 static long
361 rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
362 {
363         struct inode *inode = filp->f_path.dentry->d_inode;
364         struct rpc_pipe *pipe;
365         int len;
366
367         switch (cmd) {
368         case FIONREAD:
369                 mutex_lock(&inode->i_mutex);
370                 pipe = RPC_I(inode)->pipe;
371                 if (pipe == NULL) {
372                         mutex_unlock(&inode->i_mutex);
373                         return -EPIPE;
374                 }
375                 spin_lock(&pipe->lock);
376                 len = pipe->pipelen;
377                 if (filp->private_data) {
378                         struct rpc_pipe_msg *msg;
379                         msg = filp->private_data;
380                         len += msg->len - msg->copied;
381                 }
382                 spin_unlock(&pipe->lock);
383                 mutex_unlock(&inode->i_mutex);
384                 return put_user(len, (int __user *)arg);
385         default:
386                 return -EINVAL;
387         }
388 }
389
390 static const struct file_operations rpc_pipe_fops = {
391         .owner          = THIS_MODULE,
392         .llseek         = no_llseek,
393         .read           = rpc_pipe_read,
394         .write          = rpc_pipe_write,
395         .poll           = rpc_pipe_poll,
396         .unlocked_ioctl = rpc_pipe_ioctl,
397         .open           = rpc_pipe_open,
398         .release        = rpc_pipe_release,
399 };
400
401 static int
402 rpc_show_info(struct seq_file *m, void *v)
403 {
404         struct rpc_clnt *clnt = m->private;
405
406         rcu_read_lock();
407         seq_printf(m, "RPC server: %s\n",
408                         rcu_dereference(clnt->cl_xprt)->servername);
409         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
410                         clnt->cl_prog, clnt->cl_vers);
411         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
412         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
413         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
414         rcu_read_unlock();
415         return 0;
416 }
417
418 static int
419 rpc_info_open(struct inode *inode, struct file *file)
420 {
421         struct rpc_clnt *clnt = NULL;
422         int ret = single_open(file, rpc_show_info, NULL);
423
424         if (!ret) {
425                 struct seq_file *m = file->private_data;
426
427                 spin_lock(&file->f_path.dentry->d_lock);
428                 if (!d_unhashed(file->f_path.dentry))
429                         clnt = RPC_I(inode)->private;
430                 if (clnt != NULL && atomic_inc_not_zero(&clnt->cl_count)) {
431                         spin_unlock(&file->f_path.dentry->d_lock);
432                         m->private = clnt;
433                 } else {
434                         spin_unlock(&file->f_path.dentry->d_lock);
435                         single_release(inode, file);
436                         ret = -EINVAL;
437                 }
438         }
439         return ret;
440 }
441
442 static int
443 rpc_info_release(struct inode *inode, struct file *file)
444 {
445         struct seq_file *m = file->private_data;
446         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
447
448         if (clnt)
449                 rpc_release_client(clnt);
450         return single_release(inode, file);
451 }
452
453 static const struct file_operations rpc_info_operations = {
454         .owner          = THIS_MODULE,
455         .open           = rpc_info_open,
456         .read           = seq_read,
457         .llseek         = seq_lseek,
458         .release        = rpc_info_release,
459 };
460
461
462 /*
463  * Description of fs contents.
464  */
465 struct rpc_filelist {
466         const char *name;
467         const struct file_operations *i_fop;
468         umode_t mode;
469 };
470
471 static int rpc_delete_dentry(const struct dentry *dentry)
472 {
473         return 1;
474 }
475
476 static const struct dentry_operations rpc_dentry_operations = {
477         .d_delete = rpc_delete_dentry,
478 };
479
480 static struct inode *
481 rpc_get_inode(struct super_block *sb, umode_t mode)
482 {
483         struct inode *inode = new_inode(sb);
484         if (!inode)
485                 return NULL;
486         inode->i_ino = get_next_ino();
487         inode->i_mode = mode;
488         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
489         switch (mode & S_IFMT) {
490         case S_IFDIR:
491                 inode->i_fop = &simple_dir_operations;
492                 inode->i_op = &simple_dir_inode_operations;
493                 inc_nlink(inode);
494         default:
495                 break;
496         }
497         return inode;
498 }
499
500 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
501                                umode_t mode,
502                                const struct file_operations *i_fop,
503                                void *private)
504 {
505         struct inode *inode;
506
507         d_drop(dentry);
508         inode = rpc_get_inode(dir->i_sb, mode);
509         if (!inode)
510                 goto out_err;
511         inode->i_ino = iunique(dir->i_sb, 100);
512         if (i_fop)
513                 inode->i_fop = i_fop;
514         if (private)
515                 rpc_inode_setowner(inode, private);
516         d_add(dentry, inode);
517         return 0;
518 out_err:
519         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
520                         __FILE__, __func__, dentry->d_name.name);
521         dput(dentry);
522         return -ENOMEM;
523 }
524
525 static int __rpc_create(struct inode *dir, struct dentry *dentry,
526                         umode_t mode,
527                         const struct file_operations *i_fop,
528                         void *private)
529 {
530         int err;
531
532         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
533         if (err)
534                 return err;
535         fsnotify_create(dir, dentry);
536         return 0;
537 }
538
539 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
540                        umode_t mode,
541                        const struct file_operations *i_fop,
542                        void *private)
543 {
544         int err;
545
546         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
547         if (err)
548                 return err;
549         inc_nlink(dir);
550         fsnotify_mkdir(dir, dentry);
551         return 0;
552 }
553
554 static void
555 init_pipe(struct rpc_pipe *pipe)
556 {
557         pipe->nreaders = 0;
558         pipe->nwriters = 0;
559         INIT_LIST_HEAD(&pipe->in_upcall);
560         INIT_LIST_HEAD(&pipe->in_downcall);
561         INIT_LIST_HEAD(&pipe->pipe);
562         pipe->pipelen = 0;
563         INIT_DELAYED_WORK(&pipe->queue_timeout,
564                             rpc_timeout_upcall_queue);
565         pipe->ops = NULL;
566         spin_lock_init(&pipe->lock);
567         pipe->dentry = NULL;
568 }
569
570 void rpc_destroy_pipe_data(struct rpc_pipe *pipe)
571 {
572         kfree(pipe);
573 }
574 EXPORT_SYMBOL_GPL(rpc_destroy_pipe_data);
575
576 struct rpc_pipe *rpc_mkpipe_data(const struct rpc_pipe_ops *ops, int flags)
577 {
578         struct rpc_pipe *pipe;
579
580         pipe = kzalloc(sizeof(struct rpc_pipe), GFP_KERNEL);
581         if (!pipe)
582                 return ERR_PTR(-ENOMEM);
583         init_pipe(pipe);
584         pipe->ops = ops;
585         pipe->flags = flags;
586         return pipe;
587 }
588 EXPORT_SYMBOL_GPL(rpc_mkpipe_data);
589
590 static int __rpc_mkpipe_dentry(struct inode *dir, struct dentry *dentry,
591                                umode_t mode,
592                                const struct file_operations *i_fop,
593                                void *private,
594                                struct rpc_pipe *pipe)
595 {
596         struct rpc_inode *rpci;
597         int err;
598
599         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
600         if (err)
601                 return err;
602         rpci = RPC_I(dentry->d_inode);
603         rpci->private = private;
604         rpci->pipe = pipe;
605         fsnotify_create(dir, dentry);
606         return 0;
607 }
608
609 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
610 {
611         int ret;
612
613         dget(dentry);
614         ret = simple_rmdir(dir, dentry);
615         d_delete(dentry);
616         dput(dentry);
617         return ret;
618 }
619
620 int rpc_rmdir(struct dentry *dentry)
621 {
622         struct dentry *parent;
623         struct inode *dir;
624         int error;
625
626         parent = dget_parent(dentry);
627         dir = parent->d_inode;
628         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
629         error = __rpc_rmdir(dir, dentry);
630         mutex_unlock(&dir->i_mutex);
631         dput(parent);
632         return error;
633 }
634 EXPORT_SYMBOL_GPL(rpc_rmdir);
635
636 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
637 {
638         int ret;
639
640         dget(dentry);
641         ret = simple_unlink(dir, dentry);
642         d_delete(dentry);
643         dput(dentry);
644         return ret;
645 }
646
647 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
648 {
649         struct inode *inode = dentry->d_inode;
650
651         rpc_close_pipes(inode);
652         return __rpc_unlink(dir, dentry);
653 }
654
655 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
656                                           struct qstr *name)
657 {
658         struct dentry *dentry;
659
660         dentry = d_lookup(parent, name);
661         if (!dentry) {
662                 dentry = d_alloc(parent, name);
663                 if (!dentry)
664                         return ERR_PTR(-ENOMEM);
665         }
666         if (dentry->d_inode == NULL) {
667                 d_set_d_op(dentry, &rpc_dentry_operations);
668                 return dentry;
669         }
670         dput(dentry);
671         return ERR_PTR(-EEXIST);
672 }
673
674 /*
675  * FIXME: This probably has races.
676  */
677 static void __rpc_depopulate(struct dentry *parent,
678                              const struct rpc_filelist *files,
679                              int start, int eof)
680 {
681         struct inode *dir = parent->d_inode;
682         struct dentry *dentry;
683         struct qstr name;
684         int i;
685
686         for (i = start; i < eof; i++) {
687                 name.name = files[i].name;
688                 name.len = strlen(files[i].name);
689                 name.hash = full_name_hash(name.name, name.len);
690                 dentry = d_lookup(parent, &name);
691
692                 if (dentry == NULL)
693                         continue;
694                 if (dentry->d_inode == NULL)
695                         goto next;
696                 switch (dentry->d_inode->i_mode & S_IFMT) {
697                         default:
698                                 BUG();
699                         case S_IFREG:
700                                 __rpc_unlink(dir, dentry);
701                                 break;
702                         case S_IFDIR:
703                                 __rpc_rmdir(dir, dentry);
704                 }
705 next:
706                 dput(dentry);
707         }
708 }
709
710 static void rpc_depopulate(struct dentry *parent,
711                            const struct rpc_filelist *files,
712                            int start, int eof)
713 {
714         struct inode *dir = parent->d_inode;
715
716         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
717         __rpc_depopulate(parent, files, start, eof);
718         mutex_unlock(&dir->i_mutex);
719 }
720
721 static int rpc_populate(struct dentry *parent,
722                         const struct rpc_filelist *files,
723                         int start, int eof,
724                         void *private)
725 {
726         struct inode *dir = parent->d_inode;
727         struct dentry *dentry;
728         int i, err;
729
730         mutex_lock(&dir->i_mutex);
731         for (i = start; i < eof; i++) {
732                 struct qstr q;
733
734                 q.name = files[i].name;
735                 q.len = strlen(files[i].name);
736                 q.hash = full_name_hash(q.name, q.len);
737                 dentry = __rpc_lookup_create_exclusive(parent, &q);
738                 err = PTR_ERR(dentry);
739                 if (IS_ERR(dentry))
740                         goto out_bad;
741                 switch (files[i].mode & S_IFMT) {
742                         default:
743                                 BUG();
744                         case S_IFREG:
745                                 err = __rpc_create(dir, dentry,
746                                                 files[i].mode,
747                                                 files[i].i_fop,
748                                                 private);
749                                 break;
750                         case S_IFDIR:
751                                 err = __rpc_mkdir(dir, dentry,
752                                                 files[i].mode,
753                                                 NULL,
754                                                 private);
755                 }
756                 if (err != 0)
757                         goto out_bad;
758         }
759         mutex_unlock(&dir->i_mutex);
760         return 0;
761 out_bad:
762         __rpc_depopulate(parent, files, start, eof);
763         mutex_unlock(&dir->i_mutex);
764         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
765                         __FILE__, __func__, parent->d_name.name);
766         return err;
767 }
768
769 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
770                 struct qstr *name, umode_t mode, void *private,
771                 int (*populate)(struct dentry *, void *), void *args_populate)
772 {
773         struct dentry *dentry;
774         struct inode *dir = parent->d_inode;
775         int error;
776
777         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
778         dentry = __rpc_lookup_create_exclusive(parent, name);
779         if (IS_ERR(dentry))
780                 goto out;
781         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
782         if (error != 0)
783                 goto out_err;
784         if (populate != NULL) {
785                 error = populate(dentry, args_populate);
786                 if (error)
787                         goto err_rmdir;
788         }
789 out:
790         mutex_unlock(&dir->i_mutex);
791         return dentry;
792 err_rmdir:
793         __rpc_rmdir(dir, dentry);
794 out_err:
795         dentry = ERR_PTR(error);
796         goto out;
797 }
798
799 static int rpc_rmdir_depopulate(struct dentry *dentry,
800                 void (*depopulate)(struct dentry *))
801 {
802         struct dentry *parent;
803         struct inode *dir;
804         int error;
805
806         parent = dget_parent(dentry);
807         dir = parent->d_inode;
808         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
809         if (depopulate != NULL)
810                 depopulate(dentry);
811         error = __rpc_rmdir(dir, dentry);
812         mutex_unlock(&dir->i_mutex);
813         dput(parent);
814         return error;
815 }
816
817 /**
818  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
819  * @parent: dentry of directory to create new "pipe" in
820  * @name: name of pipe
821  * @private: private data to associate with the pipe, for the caller's use
822  * @pipe: &rpc_pipe containing input parameters
823  *
824  * Data is made available for userspace to read by calls to
825  * rpc_queue_upcall().  The actual reads will result in calls to
826  * @ops->upcall, which will be called with the file pointer,
827  * message, and userspace buffer to copy to.
828  *
829  * Writes can come at any time, and do not necessarily have to be
830  * responses to upcalls.  They will result in calls to @msg->downcall.
831  *
832  * The @private argument passed here will be available to all these methods
833  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
834  */
835 struct dentry *rpc_mkpipe_dentry(struct dentry *parent, const char *name,
836                                  void *private, struct rpc_pipe *pipe)
837 {
838         struct dentry *dentry;
839         struct inode *dir = parent->d_inode;
840         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
841         struct qstr q;
842         int err;
843
844         if (pipe->ops->upcall == NULL)
845                 umode &= ~S_IRUGO;
846         if (pipe->ops->downcall == NULL)
847                 umode &= ~S_IWUGO;
848
849         q.name = name;
850         q.len = strlen(name);
851         q.hash = full_name_hash(q.name, q.len),
852
853         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
854         dentry = __rpc_lookup_create_exclusive(parent, &q);
855         if (IS_ERR(dentry))
856                 goto out;
857         err = __rpc_mkpipe_dentry(dir, dentry, umode, &rpc_pipe_fops,
858                                   private, pipe);
859         if (err)
860                 goto out_err;
861 out:
862         mutex_unlock(&dir->i_mutex);
863         return dentry;
864 out_err:
865         dentry = ERR_PTR(err);
866         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
867                         __FILE__, __func__, parent->d_name.name, name,
868                         err);
869         goto out;
870 }
871 EXPORT_SYMBOL_GPL(rpc_mkpipe_dentry);
872
873 /**
874  * rpc_unlink - remove a pipe
875  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
876  *
877  * After this call, lookups will no longer find the pipe, and any
878  * attempts to read or write using preexisting opens of the pipe will
879  * return -EPIPE.
880  */
881 int
882 rpc_unlink(struct dentry *dentry)
883 {
884         struct dentry *parent;
885         struct inode *dir;
886         int error = 0;
887
888         parent = dget_parent(dentry);
889         dir = parent->d_inode;
890         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
891         error = __rpc_rmpipe(dir, dentry);
892         mutex_unlock(&dir->i_mutex);
893         dput(parent);
894         return error;
895 }
896 EXPORT_SYMBOL_GPL(rpc_unlink);
897
898 enum {
899         RPCAUTH_info,
900         RPCAUTH_EOF
901 };
902
903 static const struct rpc_filelist authfiles[] = {
904         [RPCAUTH_info] = {
905                 .name = "info",
906                 .i_fop = &rpc_info_operations,
907                 .mode = S_IFREG | S_IRUSR,
908         },
909 };
910
911 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
912 {
913         return rpc_populate(dentry,
914                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
915                             private);
916 }
917
918 static void rpc_clntdir_depopulate(struct dentry *dentry)
919 {
920         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
921 }
922
923 /**
924  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
925  * @dentry: dentry from the rpc_pipefs root to the new directory
926  * @name: &struct qstr for the name
927  * @rpc_client: rpc client to associate with this directory
928  *
929  * This creates a directory at the given @path associated with
930  * @rpc_clnt, which will contain a file named "info" with some basic
931  * information about the client, together with any "pipes" that may
932  * later be created using rpc_mkpipe().
933  */
934 struct dentry *rpc_create_client_dir(struct dentry *dentry,
935                                    struct qstr *name,
936                                    struct rpc_clnt *rpc_client)
937 {
938         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
939                         rpc_clntdir_populate, rpc_client);
940 }
941
942 /**
943  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
944  * @dentry: dentry for the pipe
945  */
946 int rpc_remove_client_dir(struct dentry *dentry)
947 {
948         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
949 }
950
951 static const struct rpc_filelist cache_pipefs_files[3] = {
952         [0] = {
953                 .name = "channel",
954                 .i_fop = &cache_file_operations_pipefs,
955                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
956         },
957         [1] = {
958                 .name = "content",
959                 .i_fop = &content_file_operations_pipefs,
960                 .mode = S_IFREG|S_IRUSR,
961         },
962         [2] = {
963                 .name = "flush",
964                 .i_fop = &cache_flush_operations_pipefs,
965                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
966         },
967 };
968
969 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
970 {
971         return rpc_populate(dentry,
972                             cache_pipefs_files, 0, 3,
973                             private);
974 }
975
976 static void rpc_cachedir_depopulate(struct dentry *dentry)
977 {
978         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
979 }
980
981 struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name,
982                                     umode_t umode, struct cache_detail *cd)
983 {
984         return rpc_mkdir_populate(parent, name, umode, NULL,
985                         rpc_cachedir_populate, cd);
986 }
987
988 void rpc_remove_cache_dir(struct dentry *dentry)
989 {
990         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
991 }
992
993 /*
994  * populate the filesystem
995  */
996 static const struct super_operations s_ops = {
997         .alloc_inode    = rpc_alloc_inode,
998         .destroy_inode  = rpc_destroy_inode,
999         .statfs         = simple_statfs,
1000 };
1001
1002 #define RPCAUTH_GSSMAGIC 0x67596969
1003
1004 /*
1005  * We have a single directory with 1 node in it.
1006  */
1007 enum {
1008         RPCAUTH_lockd,
1009         RPCAUTH_mount,
1010         RPCAUTH_nfs,
1011         RPCAUTH_portmap,
1012         RPCAUTH_statd,
1013         RPCAUTH_nfsd4_cb,
1014         RPCAUTH_cache,
1015         RPCAUTH_nfsd,
1016         RPCAUTH_RootEOF
1017 };
1018
1019 static const struct rpc_filelist files[] = {
1020         [RPCAUTH_lockd] = {
1021                 .name = "lockd",
1022                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1023         },
1024         [RPCAUTH_mount] = {
1025                 .name = "mount",
1026                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1027         },
1028         [RPCAUTH_nfs] = {
1029                 .name = "nfs",
1030                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1031         },
1032         [RPCAUTH_portmap] = {
1033                 .name = "portmap",
1034                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1035         },
1036         [RPCAUTH_statd] = {
1037                 .name = "statd",
1038                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1039         },
1040         [RPCAUTH_nfsd4_cb] = {
1041                 .name = "nfsd4_cb",
1042                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1043         },
1044         [RPCAUTH_cache] = {
1045                 .name = "cache",
1046                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1047         },
1048         [RPCAUTH_nfsd] = {
1049                 .name = "nfsd",
1050                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1051         },
1052 };
1053
1054 /*
1055  * This call can be used only in RPC pipefs mount notification hooks.
1056  */
1057 struct dentry *rpc_d_lookup_sb(const struct super_block *sb,
1058                                const unsigned char *dir_name)
1059 {
1060         struct qstr dir = QSTR_INIT(dir_name, strlen(dir_name));
1061
1062         dir.hash = full_name_hash(dir.name, dir.len);
1063         return d_lookup(sb->s_root, &dir);
1064 }
1065 EXPORT_SYMBOL_GPL(rpc_d_lookup_sb);
1066
1067 void rpc_pipefs_init_net(struct net *net)
1068 {
1069         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1070
1071         mutex_init(&sn->pipefs_sb_lock);
1072 }
1073
1074 /*
1075  * This call will be used for per network namespace operations calls.
1076  * Note: Function will be returned with pipefs_sb_lock taken if superblock was
1077  * found. This lock have to be released by rpc_put_sb_net() when all operations
1078  * will be completed.
1079  */
1080 struct super_block *rpc_get_sb_net(const struct net *net)
1081 {
1082         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1083
1084         mutex_lock(&sn->pipefs_sb_lock);
1085         if (sn->pipefs_sb)
1086                 return sn->pipefs_sb;
1087         mutex_unlock(&sn->pipefs_sb_lock);
1088         return NULL;
1089 }
1090 EXPORT_SYMBOL_GPL(rpc_get_sb_net);
1091
1092 void rpc_put_sb_net(const struct net *net)
1093 {
1094         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1095
1096         BUG_ON(sn->pipefs_sb == NULL);
1097         mutex_unlock(&sn->pipefs_sb_lock);
1098 }
1099 EXPORT_SYMBOL_GPL(rpc_put_sb_net);
1100
1101 static int
1102 rpc_fill_super(struct super_block *sb, void *data, int silent)
1103 {
1104         struct inode *inode;
1105         struct dentry *root;
1106         struct net *net = data;
1107         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1108         int err;
1109
1110         sb->s_blocksize = PAGE_CACHE_SIZE;
1111         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1112         sb->s_magic = RPCAUTH_GSSMAGIC;
1113         sb->s_op = &s_ops;
1114         sb->s_time_gran = 1;
1115
1116         inode = rpc_get_inode(sb, S_IFDIR | S_IRUGO | S_IXUGO);
1117         sb->s_root = root = d_make_root(inode);
1118         if (!root)
1119                 return -ENOMEM;
1120         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1121                 return -ENOMEM;
1122         dprintk("RPC:   sending pipefs MOUNT notification for net %p%s\n", net,
1123                                                                 NET_NAME(net));
1124         sn->pipefs_sb = sb;
1125         err = blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1126                                            RPC_PIPEFS_MOUNT,
1127                                            sb);
1128         if (err)
1129                 goto err_depopulate;
1130         sb->s_fs_info = get_net(net);
1131         return 0;
1132
1133 err_depopulate:
1134         blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1135                                            RPC_PIPEFS_UMOUNT,
1136                                            sb);
1137         sn->pipefs_sb = NULL;
1138         __rpc_depopulate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF);
1139         return err;
1140 }
1141
1142 static struct dentry *
1143 rpc_mount(struct file_system_type *fs_type,
1144                 int flags, const char *dev_name, void *data)
1145 {
1146         return mount_ns(fs_type, flags, current->nsproxy->net_ns, rpc_fill_super);
1147 }
1148
1149 static void rpc_kill_sb(struct super_block *sb)
1150 {
1151         struct net *net = sb->s_fs_info;
1152         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1153
1154         mutex_lock(&sn->pipefs_sb_lock);
1155         sn->pipefs_sb = NULL;
1156         mutex_unlock(&sn->pipefs_sb_lock);
1157         put_net(net);
1158         dprintk("RPC:   sending pipefs UMOUNT notification for net %p%s\n", net,
1159                                                                 NET_NAME(net));
1160         blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1161                                            RPC_PIPEFS_UMOUNT,
1162                                            sb);
1163         kill_litter_super(sb);
1164 }
1165
1166 static struct file_system_type rpc_pipe_fs_type = {
1167         .owner          = THIS_MODULE,
1168         .name           = "rpc_pipefs",
1169         .mount          = rpc_mount,
1170         .kill_sb        = rpc_kill_sb,
1171 };
1172
1173 static void
1174 init_once(void *foo)
1175 {
1176         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1177
1178         inode_init_once(&rpci->vfs_inode);
1179         rpci->private = NULL;
1180         rpci->pipe = NULL;
1181         init_waitqueue_head(&rpci->waitq);
1182 }
1183
1184 int register_rpc_pipefs(void)
1185 {
1186         int err;
1187
1188         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1189                                 sizeof(struct rpc_inode),
1190                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1191                                                 SLAB_MEM_SPREAD),
1192                                 init_once);
1193         if (!rpc_inode_cachep)
1194                 return -ENOMEM;
1195         err = rpc_clients_notifier_register();
1196         if (err)
1197                 goto err_notifier;
1198         err = register_filesystem(&rpc_pipe_fs_type);
1199         if (err)
1200                 goto err_register;
1201         return 0;
1202
1203 err_register:
1204         rpc_clients_notifier_unregister();
1205 err_notifier:
1206         kmem_cache_destroy(rpc_inode_cachep);
1207         return err;
1208 }
1209
1210 void unregister_rpc_pipefs(void)
1211 {
1212         rpc_clients_notifier_unregister();
1213         kmem_cache_destroy(rpc_inode_cachep);
1214         unregister_filesystem(&rpc_pipe_fs_type);
1215 }
1216
1217 /* Make 'mount -t rpc_pipefs ...' autoload this module. */
1218 MODULE_ALIAS("rpc_pipefs");